Wrong error message in project settings when entering a duplicate deploy key which has been used by another project

Summary

In project settings, when I enter a duplicate deploy key which has been used by another project, there will be an error message which is not fluent:

Fingerprint has already been taken, Deploy keys projects deploy key fingerprint has already been taken

As a JiHu contributor, after I changed my prefer language to Chinese, the sentence in Chinese also doesn't make sense.

I tried to search the translated string in Crowdin and search the source string in gitlab-org/gitlab, I failed to find them both.

I don't know how is this error message generated and where is the source code, this sentence should be optimized and can be translated in Crowdin.

Steps to reproduce

1. On the top bar, select Menu > Projects and find a project.
2. On the left sidebar, select Settings > Repository.
3. Expand Deploy keys.
4. Specify a title for the new deploy key and paste a duplicate public SSH key which has been used in another project.
5. Select Add Key.

Example Project

https://gitlab.com/rogertony/testdeploykey

What is the current bug behavior?

The error message in English and Chinese doesn't make sense.

What is the expected correct behavior?

The error message in English is fluent and can be understood, also can be translated in Crowdin. Besides, I want to learn how is this error message generated and where is the source code.

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com

Proposal

Switch the error message to the following:

Another project is already using this deploy key.